Jupiter Has Seven Moons
by Chokopoppo
Summary: Nothing like a cool robot boyfriend with weird sexual modules to make you appreciate the modern age of technology, and no time like the present to figure out how to use that.


"Hey, Genos, can you feel pain?"

Genos looked up from his place at the sink, one bowl half-cleaned in his hand. At the table in the next room, Saitama was staring up at him, as though he'd just thought of something. "Sometimes," he said, confidently, and went back to scrubbing the bowl. His teacher never wanted a long, detailed explanation on things - Genos was quite proud of getting his explanation down to a single word.

But clearly, it wasn't enough. When he looked at Saitama again, his teacher seemed even _more_ confused than before. "Sometimes? What does that mean?"

"I am programmed to feel physical sensation," he replied, carefully counting words, "but I only feel _pain_ in my head and torso." The clean dish made its way to the dish rack, and Genos motioned to his face and chest as he spoke. It was true - though his limbs were designed to collect data on the grip of monsters or handshakes (which would be sent directly to his brain), his body could only _feel_ sensations in a few areas. It was why he wore shirts to cover his chest, even though he didn't really need to - the touch sensors were often overzealous if not coded properly, and could quickly overstimulate his brain in a way that his human chest wouldn't have.

Saitama, on the opposite end of the spectrum, was deeply, deeply distressed, very suddenly. How many times had he assumed Genos would be "fine" where he was while his mechanics were practically destroyed? Was that like leaving a man with a gaping hole in his chest to "just deal with it"? If he'd known - he'd done his student a serious disservice. He considered apologizing to Genos, then realized he wouldn't've had it, refusing an apology from his teacher on every past occasion.

Instead, he got up from his place at the table, grabbed a dishtowel, and threw a smile. "I'll get the rest of the dishes, so you can go lie down or read if you want," he said, as kindly as he could manage. Genos opened his mouth, probably to argue, but Saitama, faster than normal with the weight of guilt on his back, silenced any protest with a decidedly over-affectionate kiss. Genos, forever too into it, groaned quietly before breaking apart, steaming gently.

"I understand," he said, face blooming shades of red, and quickly scurried off into the bathroom. Saitama watched him go, then set about with the dishes, swearing to himself to pretend he didn't know what Genos was up to in there.

Although, actually, _did_ he know what Genos was up to? Saitama dipped a coffee mug into the soapy water and considered the back of his hand. Genos was a robot, after all - they'd just discussed it a minute ago. Sure, apparently he could feel pain, so it followed that he could probably feel pleasure, too. But Saitama had seen him naked - or, at least, as naked as Genos could _get_ \- and there was nothing _there._ So it wasn't like he could be rubbing one out or anything.

In the past few weeks since Genos had explosively confessed his feelings (and to which Saitama had very flatly reciprocated with a "of course I love you too, can I get back to my video game now, Genos"), they really hadn't _done_ anything besides lie on a futon together at night and kiss. Saitama had just kind of assumed that was all Genos _could_ do, since he'd never pushed for anything else. But then again, Genos was clearly uncomfortable pushing Saitama for anything (except for training).

In the warm summer air filling the apartment, Saitama considered his options. Option one: he could be done with the dishes by the time Genos returned, have the room set up in some super romantic way, and spring on him the second he walked out with the intention of giving him the best ride of his life. Option two: he could just, like, ask.

xx

"Hey, Genos, can you jack off or anything?"

Genos, to his credit, managed a very intense, artfully curving spray with his spit-take. "Oh, that was a good one," Saitama added, then passed Genos another glass of water to remedy his coughing fit.

"Teacher is _very_ direct," Genos managed, after downing most of the second glass of water, "where did…why did you want to know?"

Saitama shrugged. "I'unno," he said noncommittally, "I just feel like a bad boyfriend right now. Because, like," he quickly added, seeing the sudden contortion on Genos' face that indicated he was about to launch into a spiel about how his teacher was a master at _all things he did_ , etc., etc., "I mean, I haven't had a boyfriend since before I decided to become a hero, but - what, we've been dating for a few weeks?" He made vague motions with his hand and leaned on the sink counter with his spare arm. "If I was dating other guys, by this time, I was definitely blowing them. So, like - hey, quit putting water in your mouth if you're just going to spit it out," he finished, brow furrowing in frustration.

"My apologies, teacher," Genos mumbled through his hands. Behind his shame-shield, his face was redder than Saitama had ever seen it.

"Hey, you know, you don't _have_ to call me teacher all the time," Saitama said, and then, almost as an afterthought, "I mean, we don't - if you don't want to do anything, that's okay. I just didn't want to assume that you didn't, just because you were a robot. So how about it?" He gave a tiny smile. "Can I blow you?"

"I, uh - " If robots could sweat, Genos would be sweating. "I, um - I need to get something from my - my things."

xx

Which brings us to where we are now. Genos holds what looks like a small black USB drive up to the light. "This is what I use!" His stern and overzealous attitude has returned, after a fair spell of being consistently caught off-guard.

Saitama examines the port carefully. "Is it…a toy?" He ventures, glances up at Genos.

"It's a module," his student explains, "it's a set of coding that allows me to experience sexual arousal." He points at the side. "There are ten levels, controlled by these buttons. Normally, I can control it without touching the port, but it can be manually overridden by someone else."

"Okay, I got it," Saitama says, and gently takes the plug from Genos, who stares at him hopefully. He really _wants_ to be into this - Genos looks so uncertain that he really wants to be enthusiastically into fucking him with this, but it's so…not sexy. He was kind of hoping Genos would have some kind of prosthetic, attachable dick that could do cool stuff, like vibrate or move around or…something. This is just a plug. It's not _bad_ , but Saitama figures it's going to be more like watching his partner masturbate than actually boning him. Still. It's better than sitting around in bed kissing until one of them has to leave. "So where does it plug in?"

Wordlessly, Genos turns his back to Saitama and brushes his hair up off of his neck. He points to the base of his skull.

Okay, so that's something. There are certain parts of anatomy Saitama can't say "no" to, and necks are definitely in the top five. "Let's sit down," he says, because somebody has to say it, "standing up is going to suck. Here." He sits confidently on the floor and leans against the wall, spreading his knees to accommodate Genos, and pats the ground between them. After a moment of hesitation, the robot joins him on the floor, back facing him, and Saitama brushes the hair away from his neck, finds the USB port, and plugs the drive in.

Wait, no. That was the wrong way. He turns it over and tries again.

Shit. _No_. It was the first way.

When the plug goes in, Saitama kind of hopes for a gasp, or a moan, or something sexy and kind of indecent, but instead, there's virtually no reaction at all. Genos is still sitting stark upright, looking nervous and vulnerable, and the tiny screen on the patch reads "0". He sighs - things can't always work out like they would in a high-budget sci-fi porno, after all - and presses the little arrow to raise the level by one.

There's a gentle, perceptible change in Genos - his shoulders slump and his head lolls to the side, the tension that had been wracking his frame leaking out. Saitama wraps a supportive arm around his chest, pulling him back gently to lean into his teacher, then turns the level up to two.

Genos gives a gentle little moan in response, which Saitama takes as a good sign. His hands roam gently over Genos' chest, then under the shirt he borrowed from Saitama earlier that morning. There's a whimper, shaking and quiet. "Is this good?" Saitama asks, looking at Genos' face. Nod nod. "Do you want more?" Nod nod nod.

At speed three, Genos' legs part and his head rolls back onto Saitama's shoulder, who kisses him delicately on the forehead. "Teacher," he gasps, chest heaving with artificial breath, "teacher, please - mm," he breaks off and gasps again, a tiny hiccup of air followed by a slow, warbling moan. Saitama finds himself…affected.

"Genos," he whispers, letting breath ghost over his student's ear, "what else can I do? Show me how to make you feel good."

Genos shivers and hums in response, mumbles "here, here…" and goes to pull his shirt off. Saitama hasn't ever really noticed it before, but his mechanics and wires shift realistically, like muscles of a human back. Fuck, he thinks, suddenly conscious of growing heat in his groin, backs were also _definitely_ on that top-five anatomy parts list. He rests his hands on Genos' shoulders and gently strokes down over shifting metal. There's a startled hiccup-gasp in response, which Saitama takes as an encouragement, and presses one finger between the connecting plates at Genos' spine, slides it as far in as it can go - runs it all the way down to the floor.

The result is satisfying and overwhelming - Genos moans ecstatically and crumples forward, shoulders shaking, hands clenching into fists at his chest. In spite of himself, Saitama grins. "So the connecting plates are good?" He asks, running fingers over the metallic back enthusiastically.

There's gasping, and then a very weak "yesss," in response. Genos struggles to get his breath back. He hadn't anticipated his teacher being so ready to explore - he'd _meant_ to show him the oversensitive chest plates under his armored ones, and then his steadily heating core under _that_ , but already, he was caught off-guard. Curious hands were exploring him, now, looking for hotspots and finding them with an almost unnerving frequency. "Anywhere with - ah - exposed wires is good," he manages, and slowly slumps back into Saitama's arms.

"Mmm," his teacher hums, noncommittally, and then he feels the drive level go up to four - then, quickly, to five.

Genos' entire body shudders, and he can't hold back the loud, embarrassing moans pouring out of his mouth, gasping frantically as he feels Saitama's fingers on his neck, probing, sliding between the wires. The drive sends fast, throbbing waves of heat coursing through his body, intensifying in speed and temperature at every level, making him shake, and something about his teacher's presence - fuck. He gasps, writhes in Saitama's supportive arms. There's so much - so much heat and so much Saitama and so much contact -

He cries out desperately as Saitama begins to rhythmically finger the inside of his neck, brushing and squeezing against the tangle of wires. From some old instinct, his hips buck, as though anything below his waist can stimulate him the way the hands on his body do. " _Teacher,_ " he moans, "God, _please..._ " He grabs at the unoccupied hand supporting him and pulls it from his waist to his chest, pressing Saitama's unresisting fingers under the armored plates covering the faulty touch sensors and loose wires and cable boxes, lays the rest of his weight into his teacher.

Jesus, he's so fucking close. Normally, he has to push all the way to nine or ten to trigger the release program, but he's right on the edge and they're barely halfway through the settings. As a curious hand flicks his chest cavity open and begins to run experimental touches delicately over the sensitive plastic and glass underneath, he contemplates his teacher - not a master, but _so eager_ , breathing hard beneath and around him. As if reading his thoughts, Saitama bites his ear, prompting a sudden (if not particularly sexy) noise - something like a "hhhghouauohgod" - and whispers, "is this your heart, here?"

His fingers brush up against Genos' core, pulsing blue, and his whole body jerks with his cry. "Yes, teacher, _master_ \- so good, _please_ , yes," he babbles, incoherently. "More, more, please - so close, so, so…" His body heaves with the effort of rational speech - between the fingers in his neck and the ones in his chest, he can barely see different colors - everything throbs and blurs together.

With a determined tongue, Saitama presses the up arrow on the patch.

Genos _screams_ , arches his back desperately, twists in Saitama's arms in the overwhelming waves pounding through his body. Every ragged gasp comes out a moan, even as Saitama pulls him close, whispers gentle reassurances into his ear he can neither understand nor obey, runs a hot, sweating palm over the hot, smooth metal of his core. "Pleasepleaseplease, so close, please, _fuuuuck_ ," he manages, all in a shaking breath, kisses Saitama hot and fast.

Everything is so hard and fast and there is a hand on his core and another fucking his windpipe and Saitama is all around him, stroking and pumping and kissing and breathing just as hard in his ear, whispering frantically and sometimes Genos catches words, low and _hungry_ and "God you're so beautiful, I wanna make you mine, so good like this, come on, Genos, come on, come for me," and he cannot breathe with words like that in his ear and fuck, fuck, _fuck_ and the world goes white

He comes to a few seconds later, the echo of an animalistic scream (his own?) ringing in his ears, shaking and gasping for breath, and Saitama is holding him around the waist again and stroking his hair gently, saying benign, encouraging things in a normal tone of voice. After the release function executes, the patch defaults to off, and has to be rebooted, leaving Genos shuddering with gentle after-affects.

"You okay, Genos?" Nod nod. "You wanna just sit here for a minute?" Nod nod nod.

Saitama can sit for about three minutes before he starts to get antsy. He hadn't considered it a possibility, but fuck if watching Genos have what looked like the best damn orgasm of his life hadn't given him a couple things to think about in the bathroom. Which he really, really needs to go think about right now, or else suffer a shitty case of blue-balls for the rest of the day. "Genos, I can come back and cuddle," he starts, "but I, uh, I gotta go take care of myself. That was, um…." He looks for an accurate word in his vocabulary. "Really cool."

 _NO_. No, dammit, it wasn't _really cool,_ it was _fucking hot_ or something like that. Not that it wasn't cool to see Genos get off like a boss, but -

"Teacher, let me help you," Genos said suddenly, twisted onto his side to face Saitama. "It's only right - after you gave me so much, I have to pay you back." One hand pressed gently into Saitama's chest, slid down to the hem of his shirt. Saitama blinked twice.

"Okay," he said, and laid back on the floor.

"Teacher, let me - "

"Okay, wait, no," Saitama says suddenly, and Genos looks up in a panic, "I don't mind it normally, but if you're gonna get me off, you have to say my actual name. It's important to me." Genos opens his mouth in protest, but Saitama - maybe just instinctively - pushes his thumb into the side of Genos' mouth. "Say it," he says again, insistently.

"S-Saitama," Genos says nervously, dropping the honorific.

"Yeah, like that," Saitama says, and gives Genos a trademarked doofy smile. "Okay, inow/i do whatever cool stuff your robot body can do. I have faith in your abilities."

"I don't - I don't have anything very cool, teacher," Genos says, nervous - and Saitama sighs at the quick slip back into formal language - "I'm sorry - if I knew we were doing this tonight, I would have gotten something…cooler."

"Well, do whatever you can," Saitama replies, and sets his head back against the carpet. He's not sure exactly what Genos thinks he needs to do - honestly, he's so hot and bothered that his disciple could just go straight for a hand job and it'd take about two minutes - but it seems fair to give him a shot. After all, getting other people off kind of rocks, and he understands why Genos would want to do it.

There's something hot and wet on his neck, and he sighs contentedly, sets a loose, comfortable palm on Genos' neck, and then they're kissing, mouth on mouth, lips sliding. Secretly, Saitama has always felt that kissing is a little bit gross, with spit getting all over his face and tongues kind of tasting like sad worms, but kissing Genos is different. Without fail, Genos' saliva tastes like green tea, and his tongue is unnaturally soft and slippery, rather than bumpy and tough and weirdly probing. He also doesn't have any weird ideas about forcing his whole tongue into Saitama's mouth all at once, opting instead for lip action and gentle, almost lizard-like flicks with the tip between the teeth. A weird thing to think about, maybe, but he appreciates these little details.

He also appreciates Genos biting and sucking on his lower lip, and his breath comes out in a shake. There's a hand pushing up between his hoodie (damp) and his t-shirt (soaked with sweat), feeling the connections between muscles with a hungry curiosity. It's pretty flattering. Also, weird.

"Uh, I can just take this off, if you want - " he starts, as they break away, but Genos is already hurriedly pushing the thick material up and off his torso. The sudden lack of heat, either from the hoodie or from Genos, makes his skin tighten - but then hot, whirring metal pushes him down onto the floor, and excited teeth bite him sharply under the ear. His hips jerk involuntarily.

"Everything about you is admirable, teacher," Genos mumbles into the sensitive skin of Saitama's neck, and he sighs, even as a hand strays down the side of his waist eagerly.

"Say my n-auh," he gasps, interrupted by a surprisingly present tongue running from between his collarbones up to his chin, but tries again, undeterred. "Genos, _say my name_ , already." It comes out sounding like a whine - it _is_ a whine. All he wants is _one thing_.

Instead, Genos breathes hard, sits up over Saitama, pushes his shirt up high enough to reveal the musculature of his chest, and stares. The lights on his body dim, pulse bright light in ebbing waves, and his eyes roam. Normally, Saitama would be embarrassed - but in this situation, it doesn't seem appropriate to shy away. Besides, he's painfully hard, and Genos already looks like a starving man watching a feast be set out. It'd be better to get him to act, and fast. He tips his head back, stretching his neck out in display, runs a hand down the full length of his chest, and gives a long, drawn-out groan.

Above him, he watches Genos press two fingers into his own mouth, hears a needy whine. Runs his hands up along the insides of his thighs and watches him shudder above him. "Come on, Genos," he murmurs encouragingly, "come on. Say my name."

Genos' chest heaves, nervous, and that tongue, slick and smooth and ever so slightly too red, runs over his lips to wet them. "S…Saitama," he stammers, and Saitama's breath catches involuntarily because god if the sound of _his name_ coming out of _that mouth_ doesn't send fire up his spine then nothing in the world ever could.

"Again," he gasps, "say it again."

He's breathing hard, now, pale face flushed and lips stammering, but Genos manages to whisper "Saitama," into the hot, still air. Saitama moans, unashamed, grinds his hips up against the unresisting body above him. And that's all it takes.

Genos springs into action, presses his whole body flush against his teacher's, kissing and biting desperately at his neck, hot and needy, voice breaking with the urgency of gasping Saitama's name over and over again into his ear, hands sliding and grasping, and Saitama is overwhelmed, groaning and twisting - sometimes, he tries to say a word, but all that ever comes out is "oh, _fuck_ ," or even just "hhhnggg," whimpering, wrapping arms around Genos for support.

Everything is so hot and so fast and so enthusiastic and so _good_ that he almost doesn't notice when Genos moves his attention down to his breathless, heaving chest, kissing down over muscles, until there's a frantic hand rubbing against his crotch, and all his breath shoots out in an undignified yelp. "Genos, hey," he manages, and then between the two of them the shorts are getting kicked off.

"Saitama," Genos whispers back, and slides his mouth all the way down.

Saitama _wails_ , back arching in surprise and heat, fingers scrabbling desperately against the wooden floor. One foot jerks up in stimulation, the other digs deep into the floorboards. "Oh, fuck, Genos, _fuck_ ," he moans, barely aware of the world around him. There's just Genos, and Genos' hands, and his mouth, god, that _mouth_ , tongue stroking flat or swirling in quick alternation. And his fingers, wrapped tight around the base of his dick, metal but ebbing heat with one hand - the other - stroking his leg reassuringly, at first - nothing else in the universe matters. His heart is pounding fiercely in his chest, his blood flowing thick and hot between his head and his dick, muscles tensing, ready to explode.

He's already so fucking ready - the fact that he's still hanging on is a true testament to his stamina, he thinks - his voice is reduced to short, pitching moans at every hitching breath - he can hear and _feel_ it every time Genos moans around him, long and throaty - slippery fingers are pressing insistently into him and it's too good to disagree with - his skin grows tight and he realizes Genos has pushed his cock all the way into his throat and is _swallowing around it_ \- he can't think in words, can't think in feelings, he can only think that god Genos is so good and so hungry and so hot around him and the fingers pistoning into him curl around _something_ and pressure explodes hot on either side of his dick and oh, _fuck._

Saitama comes hot and ragged into Genos' mouth, who pulls off and slides that tongue back over his lips, letting it dribble back off onto his chin, which is enough to make the first wave of aftershock hit him in the eye. "Oh, sorry," Saitama gasps, suddenly - not in the heat of the moment - very apologetic and embarrassed, but Genos is grinning like an absolute ledge.

" _Saitama,_ " he groans, and Saitama makes an unfortunate "hrhruhorhg" noise and hits him in the face again.

"Okay, wait, let me clean that off," Saitama starts, but Genos rubs a hand over it, smearing it across his cheek - goes to smell it - and then, in a twist of the expectation, pushes it into Saitama's face, cackling, to which Saitama gasps "ew, gross, _no_ ," and tries to roll away, laughing just as hard.

They end up curled, one against the other, gasping for breath and laughing. The weird thing about sex, Saitama decides, is how _funny_ it makes everything. He gives Genos an appreciative slap on the ass. "Good job, bucko, now _let's hit the showers_ ," he says, in his best impression of what he's _pretty_ sure sports-coaches sound like, and Genos laughs again, wraps his arms tighter around Saitama's chest, presses his face into the back of his neck.

Saitama lies there, in his arms, and catches his breath, and thinks how lucky he is to be here.

And then he reaches out for the TV remote, and puts on the news. And after ten minutes or so, he falls asleep, and Genos powers off, and nothing stirs until the morning.


End file.
